4,8,12,16-TETRA-TERT-BUTYL-S-INDACENO[1,2,3-CD 5,6,7-C'D']DIPHENALENE- A 4-STAGE AMPHOTERIC REDOX SYSTEM/

A four-stage amphoteric redox hydrocarbon (5) containing two phenaleny l units was prepared. X-ray crystallography of 5 reveals a delocalized D-2h structure, which is consistent with the presence of only five si gnals in the H-1 NMR spectrum of 5 at -60 degrees C, The cyclic voltam mogram of 5 exhibits four reversible redox waves with a small numerica l sum (E-1(sum)) of first oxidation (E-1(ox)) and reduction (E-1(red)) potentials. Four redox states of 5 were successfully generated from t he neutral 5 and were characterized by NMR, ESR, and UV-vis-near-IR sp ectroscopies and theoretical calculations. These spectral data reveal that phenalenyl units play an important role in the high amphotericity of 5 and the stability of the redox states generated.